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Materials Testing Instruments Ma.Tec. range of ASTM-standard instruments are designed for the measurement of abrasion and attrition resistance, crush strength and bulk density. ROTAB-AS Abrasion Resistance
Therefore, abrasion resistance is a property of the utmost importance for industrial catalysts. It also provides meaningful information for other industrial products (pharmaceutical tablets, fertilizers, sugar and ceramics). ROTAB-AS/S, a rotating cylinder abrasimeter, is an instrument for determining the abrasion resistance of solid materials, either in a granular or a pellet shape or as a coarse powder. The rotation rate of the vessel can be varied in the range 30-90 rpm. The constant-rotation version of the instrument (ROTAB-AS) features a fixed rotation rate of 65 rpm. Both instruments were designed according to the ASTM standard method D4058, covering the particle size range 0.85-20 mm. Measurements can also be performed on larger size materials.
ATTRI-AS Attrition Resistance of Powders
ATTRI-AS is an instrument for measuring the attrition resistance of any type of powder. It is based on the air jet principle and strictly follows the ASTM standard method D5757. However it can also be used according to different procedures. Typical powders to be measured by this technique range in size between 10 and 180 micrometers. The equipment consists of a special stainless steel attrition tube, where the powder is stressed by high-speed air jets, coming from precision-drilled submillimeter nozzles. They provide an accelerated simulation of the attrition phenomena occurring in reality during a period of months. Ahead of the attrition tube a glass-made settling chamber is placed, allowing to look at the powder inside during the treatment. Back to the attrition tube both air pressure and flow rate measurement instruments are located. An assembly for fines collection is placed behind the settling chamber. The air flow can be humidified by inserting a water saturator. The percent loss of fines after a specified time of treatment gives a measurement of the attrition resistance. ATTRI-AS has been designed to allow fast operation and is compliant with CE specifications. CRUSH-BK/CRUSH-SP Crush Strength
CRUSH-BK is an instrument for measuring the crush strength of solid materials having regular, or almost regular, geometrical shape, like spheres, cylinders, rings and similar. Their size can be as small as 1 mm, up to about 20 mm. Basically CRUSH-BK is a dynamometer measuring the force progressively applied to the solid object during the advancement of a piston. The applied force increases until the solid breaks and collapses into small pieces and eventually powder. The corresponding value of the collapsing force is defined as crush strength. When the material consists of irregular particles, the measurement of the so-called 'single pellet' crush strength cannot be performed, but the 'bulk' crush strength must be determined instead. CRUSH-BK allows to make both single pellet and bulk measurements with the same instrument without any modification of its parts. The characteristics of CRUSH-BK can vary according to customer's requirements. CRUSH-SP, applying much lower loads (30 kg max), is recommended when bulk measurements are not required and the pellets under examination are not very strong. DENSI-TAP Bulk Density
DENSI-TAP is a bench instrument and is compliant with CE specifications.
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Abrasion in solid materials occurs because of the rubbing of solid pieces against each other (or any mechanical component). The rubbing typically takes place during transportation, in vessels or pneumatic, while loading and during any handling of the material. Abrasion leads to the formation of finer dust and to the consequent loss of precious material or valuable features.
Any powder, when moved, is subjected to attrition phenomena, leading to the undesirable formation of fines. The measurement of attrition resistance is therefore indispensable, in particular for powders used as catalysts in both fluid bed and slurry reactors.
The crush strength represents the resistance of the solid to compression, a property of paramount importance not only for industrial catalysts, but also for ceramics, pharmaceutical tablets and many other solid materials. In the case of catalysts it is noteworthy that many plant shutdowns occur due to mechanical failure of the catalyst, not to its loss of activity. Therefore an accurate measurement of catalyst mechanical properties is mandatory.
DENSI-TAP is an instrument designed to measure the bulk density of both powders and formed particles (maximum size about 5 mm). It complies with ASTM standard D4164. The sample is poured into a graduated cylinder (usually 250 ml) hinged on a tapping device. A four-digit taps counter is included, which can be programmed to the required number of taps (usually 1000). When tapping is completed, the tapped volume is read on the cylinder graduation.